ABSTRACT The ultimate goal of this project is CLIP-CT, an FDA-cleared and CE-marked smartphone-based test (?30 min) for Chlamydia trachomatis (CT) infections in women in over-the-counter (OTC) and point-of-care (POC) settings. CT is the most common bacterial cause of sexually transmitted infections, with almost 3 million new cases in the US each year. Untreated women, mostly in the 15-24 age group, are at high risk of serious sequelae including pelvic inflammatory disease, ectopic pregnancy, and infertility. CT infections are curable with a single pill, but the fact that they are asymptomatic in up to 90% of those infected necessitates screening of high-risk populations using accurate testing methods. Currently recommended Nucleic Acid Amplification Techniques (NAATs) are expensive and have slow turnaround times, severely limiting their applicability for expanding testing coverage. Rapid POC tests can curb disease transmission by enabling a same-day test and treat approach and immediate partner notification. An OTC test that can also be used in POC settings will also expand testing to the large swath of at-risk women who do not seek testing due to embarrassment/confidentiality concerns. Luminostics' CLIP-CT is based on the use of nanophosphors ? persistent luminescent nanoparticles ? as lateral flow assay (LFA) reporters in an immunoassay for CT. A phone case-like smartphone adapter, in combination with a mobile app, is used for result readout and analysis from the nanophosphor-LFA using the phone's flash and camera. Current colorimetric LFAs for CT are >95% specific due to the availability of good monoclonal antibodies, but have very poor clinical sensitivity due to their high limit of detection (LOD). We hypothesized that the vastly improved LOD of nanophosphor-LFAs compared to colorimetric LFAs could result in clinical sensitivities approaching NAATs (i.e., >90%). We obtained initial validation for this hypothesis in Phase I studies, where CLIP-CT prototypes with a 100-fold lower LOD than an FDA-cleared colorimetric LFA for CT achieved a sensitivity of 91.7% and a specificity of 95% compared to an FDA-cleared NAAT in a small retrospective clinical. Having validated the feasibility of nanophosphor-LFAs for sensitive CT detection, the following Specific Aims are proposed for Phase II: Aim 1 will iteratively design, develop and validate the ancillary hardware and software components of CLIP- CT around the Phase I-developed assay. Aim 2 will perform comprehensive analytical performance studies and a human factors validation study. In Aim 3, the clinical performance of CLIP-CT will be validated in a large (n=1,250) clinical study using prospectively collected specimens. Luminostics has assembled a team of bioengineers, chemists, software engineers, microbiologists, clinicians, and manufacturing experts to maximize the odds of success. The expected outcome of this Phase II project is the significant de-risking of the final trial targeting FDA 510(k) OTC clearance for CLIP-CT and the further validation of nanophosphor-LFAs as a platform technology with potential applications in a variety of medical conditions that could use more sensitive POC tests.